The present invention relates to a method of manufacturing a compact, multilayer, single strand reinforcing cord for elastomeric products in a stranding process in which metal wires of the same diameter are fed in a plurality of stranding points arranged one after the other whereby two or more metal wires are fed in the first stranding point or a single metal wire is fed through the first stranding point and six metal wires are fed into the second stranding point. This invention also relates to a reinforcing cord produced by this method.
A method of this kind and reinforcing cords produced by such a method are known from the German publication No. DE-OS 29 34 012. In this known method a stranding point is provided for each layer of metal wires. In order to guarantee that the individual metal wires in a completed cable formation occupy approximately the intended location, the metal wires are first jointly subject to a dummy twist before they are fed to the actual stranding device. The provision of the dummy twist should also insure that depending on the position of the individual metal wires in the completed cable formation the requisite length of each metal wire is supplied. In addition, the corresponding length of each metal wire is safeguarded by controlled rollers whose rotary speed is dependent on stress.
In this known method, however, when manufacturing reinforcing cords having more than two layers it cannot be guaranteed that each metal wire settles always in the intended position with respect to the underlying layer and accordingly it has been found that in reinforcing cords produced according to the the prior art method and exchange of locations of the metal wires over a length of the cord takes place. This exchange of locations has the consequence that the resulting reinforcing cord becomes less compact. Moreover, the equalization in length between individual metal wires cannot be maintained with sufficient accuracy. If the individual metal wires exhibit excessive length then in further processing, for example during laying or reeling, the small folds are shifted together into large carpet like folds and such folds then protrude in the form of loops from the cable binding or formation.